You are leaving out the fact the defunding effort was not because they disagreed with the budget, but to reign in a President who has gone rogue, thumbing his nose at the Constitution, and usurping power he doesn’t have. Do you really think if a Republican president starting exceeding his constitutional authority as commander-in-chief the Democrats wouldn’t try to stop him by denying funding? I believe the Republicans would join them readily. If I remember right, the Democrats did try, or at least call for defunding the Iraq war.
The Republican leadership decided this was the best method to stop Obama, after they gave him everything he wanted in the “Cromnibus” bill. They were obviously lying to America, and simply buying time to surrender while creating the scenario that they couldn’t win.
The fact is, the Republicans started surrendering this battle as soon as it was announced. They could have very easily gotten the same information out to the low information voters if they had stood firm, and aggressively attacked the President, and his over reach. Granting amnesty to illegal aliens is unpopular, and cuts across party lines. The Republicans wanted this outcome, and they wanted people to be able to defend them with some degree of credibility that they couldn’t win. The truth is, they set up the unwinnable situation, they weren’t victims of it.
Remember Iran-Contra, where Reagan sold weapons to Iran to fund the contra effort against the Sandinistas? Remember James Watt, whom Reagan appointed to prevent the EPA from carrying out its mandate? The Democrats were equally furious about what they saw as executive usurpation of Congressional authority. And yet the first time anyone's ever heard of a government shutdown via congressional gridlock was under the GOP.